Abstract: A fluid flow control apparatus precisely controls a slight flow of fluid being mixed with a carrier gas. The apparatus includes a container for containing the fluid and a conduit for conducting the fluid, one portion of the conduit having a smaller diameter than the other, the smaller diameter portion of the conduit Including a needle valve for controlling the flow of the carrier gas into the conduit. A fluid transmission line connected at one end to the conduit and at the other end to the container conducts fluid from the container into the conduit to be mixed with the carrier gas before the mixture is introduced into a reacting chamber.